Double triflow muffler

ABSTRACT

An exhaust muffler for external side mounting on sports cars comprises an elongated tubular housing having internal partitions which carry two pairs of overlapping perforated gas flow tubes separated by a central expansion chamber to provide a series arranged, double triflow pattern for gas flow and sound silencing.

United States Patent Charles L. Palmer Munith, Mich. 67,062

Aug. 26, 1970 Oct. 19, 1971 Tenneco Inc. Racine, Wis.

Inventor Appl. No. Filed Patented Assignee DOUBLE TRIFLOW MUFFLER 6Claims, 4 Drawing figs.

US. Cl

Int. Cl

Field of Search [56] References Cited UNITED STATES PATENTS 792,8046/1905 Williams 181/53 2,189,424 2/1940 Leadbetter 181/54 PrimaryExaminer-Robert S. Ward, Jr. Attorney-Harness, Dickey and Pierce BRIEFSUMMARY OF THE INVENTION It is the purpose of this invention to providea muffler construction that will fit neatly along the side contours ofvarious American-made sports cars and will meet the legally specifiedsound level requirements at a minimum back pressure.

The invention accomplishes this by means of a relatively long tubularhousing of relatively small cross section which has two sets ofoverlapping perforated tubes arranged in series and separated by acentral chamber. This arrangement provides two trifiow attenuationsystems, which in conjunction with the central chamber and otherchambers, provide a high degree of sound attenuation of frequencies inthe high and medium range with minimum horsepower loss due to backpressure of the muffler.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a somewhat schematic sideelevation of single exhaust system containing a muffler in accordancewith this invention, it being recognized that in most sports carapplications two of the mufflers will be used externally, one along eachside of the automobile;

FIG. 2 is an enlarged, long cross section of the muffler shown in FIG.1;

FIG. 3 is a section along the line 3-3 of FIG. 2; and

FIG. 4 is a broken-away cross section showing a different housingconstruction that may be used at opposite ends of the muffler.'

DETAILED DESCRIPTION OF THE INVENTION An internal combustion engine 1has an exhaust manifold 3 which discharges gases into an exhaust system5 that includes an exhaust pipe 7 which delivers gases to a muffler 9,constructed in accordance with this invention, which in turn dischargesgases to a tailpipe or tailpipe spout 11 that empties into atmosphere.

The muffler 9 has a long, small tubular housing 13 which may be formedfrom tubular stock that is flattened on opposite sides as indicated at15 in FIG. 3 to enable it to fit neatly along the outside of anautomobile. In the modification of FIG. 2, the opposite ends of thehousing 13 are closed by an inlet header l7 and outlet header 19 whichare in he form of transverse partitions having flanges spotwelded to thehousing 13. Inside of the housing 13 are a series of transversepartitions 21, 23, 25, 27, 29, and 31 which subdivide the housing intoadjacent but separate internal chambers 33, 35, 37, 39, 41, 43, and 49.The header l7 and the partition 21 have aligned collars 51 and 53 whichsupport an inlet bushing 55 so that it is concentric with the centerlineand longitudinal axis of the housing 13. The outlet header 19 and thepartition 31 have aligned collars 59 and 61 which support an outletbushing 63 so that it is coaxial with the inlet bushing 55. The inletbushing 55 and the outlet bushing 63 are spotwelded respectively to thecollars 51 and 53 and 59 and 61 and since the headers and the partitionsare spotwelded to the shell 13, a high degree of structural strength forthe bushings is achieved.

The exhaust pipe 7 fits in the inlet bushing 55 and is secured to it bya clamp 57. The outlet bushing 63 receives the inlet end of the tailpipel1 and is clamped to it by a suitable clamp 65.

Two substantially identical sets 67 and 69 of overlapping flow tubes aremounted within the housing l3 to provide two separate triflow chambers.The set 67 comprises an inlet conduit 71 and an outlet conduit 73 whilethe set 69 comprises an inlet conduit 75 and an outlet conduit 77. Theconduits in each set preferably have a substantial length of mutualengagement and are spotwelded to each other as indicated at 79 so thateach set acts as an integral structure to eliminate the need for acentral supporting partition. The inlet end of the inlet conduit 71 ismounted in a collar 81 in the other wise imperforate partition 23 andthe outlet end of the outlet conduit 73 is mounted in a collar 83 in theotherwise imperforate partition 25. In the set 69 the inlet end of theconduit 75 is mounted in a collar 85 of the otherwise imperforatepartition 87 and the outlet end of the conduit 77 is mounted in a collar87 in the otherwise imperforate partition 29. The inlet conduit 71terminates a substantial distance upstream from the partition 25 and theinlet conduit 79 terminates a substantial distance upstream from thepartition 29. The outlet conduit 73 has it inlet end spaced asubstantial distance downstream from the partition 23 and the outletconduit 77 has its inlet end spaced a substantial distance downstreamfrom the partition 27. Each of the tubes 71, 73, 75, and 77 has asubstantial part of its length, preferably in the area which overlapsthe other tube of the set, perforated and the perforations arepreferably in the form of louver patches 89.

In the modification of FIG. 4 the internal construction of the muffleris substantially the same as that of FIG. 2 but the housing 13' isreduced in diameter by swagging or otherwise, as seen at 101, and theoutlet (and inlet) bushing 63 is formed as a monolithic or integral partof the housing thereby eliminating the need for the end headers 17 or 19and the adjacent support partitions 21 and 23.

In operation, gas from the exhaust pipe 7 enters the muffler through theinlet bushing 55 and passes into the enlarged area and volume of theinlet chamber 35. From the chamber 35 the gas enters the reduced area ofthe inlet pipe 71 until it is discharged into the enlarged area formedby the volume of chamber 37 adjacent the partition 25. The gas thenreverses its direction of flow and heads back through chamber 37 towardthe inlet of the muffler until its direction of fiow is reversed bypartition 23 to cause it to enter the smaller outlet tube 73. It isdischarged from tube 73 into the central expansion chamber 39 from whichit enters the smaller inlet conduit 75 of the triflow set 69 to follow asimilar pattern of double reversal, i.e., three paths of flow in chamber41, and discharge by outlet conduit 77 into the enlarged chamber 43.From chamber 43 the gas flows from the outlet bushing 63 into thetailpipe 11 and then to atmosphere.

In the case of the mufiler embodying the modification of FIG. 4, theoutlet chamber 43 (and inlet chamber) would be shaped as indicated inFIG. 4.

The various changes in cross section of the flow path which the gas mustfollow as it travels from chambers to conduits remove a substantialamount of acoustic energy from the pulsating gas. The central expansionchamber 39 is of a relatively large size and provides for ratherbroad-banded note control or tuning as do, to a lesser degree, theexpansion inlet and outlet chambers 35 and 43. The optimum volume ofexpansion chamber 39 is detennined by the size of the engine beingsilenced. Its placement between the two triflow section 67 and 69minimizes turbulence and back pressure and improves attenuation. Thelouver patches 89 in the conduits in conjunction with the crossflowchambers 37 and 41 attenuate high frequencies and roughness and providesome crossflow to keep back pressure as low as possible. The totalconstruction is very effective in removing high and medium frequenciesbut is deliberately designed to be only partially efiective on the lowerfrequencies so that the deep tone sound of generated horsepower isaudible.

The relatively simple construction of mufi'ler 9 therefore provides lowback pressure, high performance sound-attenuating means in a long, slimhousing which is shaped for external mounting on the outside of anautomobile to provide the show and the go desired in sports cars. Eitherend of the structure shown may be the inlet and the same unit may beused with different models and different makes of automobiles ofsubstantially the same engine displacement. As indicated above, themuffler 9 is normally used in pairs, one on each side of the vehicle.

I claim:

1. A mufiler comprising a long, slim housing having an inlet means atone end and an outlet means at the other end, transverse partition meansin the housing providing a housing-wide expansion chamber locatedsubstantially at the longitudinal midsection of the housing, first gasconduit means mounted in the housing providing a first triflow gas pathreceiving gas from said inlet and discharging it into said expansionchamber, and second gas conduit means mounted in the housing providing asecond triflow gas path receiving gas from said expansion chamber anddischarging it into said outlet means.

2. A muffler as set forth in claim 1 wherein said inlet and outlet meanseach include a bushing extending externally of the housing and ahousing-wide expansion chamber forming a part of the gas flow paththrough the muffler.

3 A muffler as set forth in claim 1 wherein said first and second gasconduit means each include a pair of overlapping perforated gas flowtubes and a housing-wide chamber containing said tubes.

4. A muffler as set forth in claim 3 wherein said inlet and outlet meanseach include a bushing extending externally of the housing and ahousing-wide expansion chamber forming a part of the gas flow paththrough the muffler.

5 A muffler as set forth in claim 4 wherein said first and secondconduit means are substantially identical in construction and said inletand outlet means are substantially identical in construction.

6. A muffler as set forth in claim 5 wherein opposite longitudinal sidesof the muffler are substantially symmetrical with respect to saidexpansion chamber and the inlet and outlet means are interchangeable.

1. A muffler comprising a long, slim housing having an inlet means atone end and an outlet means at the other end, transverse partition meansin the housing providing a housing-wide expansion chamber locatedsubstantially at the longitudinal midsection of the housing, first gasconduit means mounted in the housing providing a first triflow gas pathreceiving gas from said inlet and discharging it into said expansionchamber, and second gas conduit means mounted in the housing providing asecond triflow gas path receiving gas from said expansion chamber anddischarging it into said outlet means.
 2. A muffler as set forth inclaim 1 wherein said inlet and outlet means each include a bushingextending externally of the housing and a housing-wide expansion chamberforming a part of the gas flow path through the muffler.
 3. A muffler asset forth in claim 1 wherein said first and second gas conduit meanseach include a pair of overlapping perforated gas flow tubes and ahousing-wide chamber containing said tubes.
 4. A muffler as set forth inclaim 3 wherein said inlet and outlet means each include a bushingextending externally of the housing and a housing-wide expansion chamberforming a part of the gas flow path through the muffler.
 5. A muffler asset forth in claim 4 wherein said first and second conduit means aresubstantially identical in construction and said inlet and outlet meansare substantially identical in construction.
 6. A muffler as set forthin claim 5 wherein opposite longitudinal sides of the muffler aresubstantially symmetrical with respect to said expansion chamber and theinlet and outlet means are interchangeable.